Meneghetti et al. U.S. 2007/0041918, discloses hexagonal boron nitride treated with a zirconate and employed up to 75% by weight in polymers to prepare samples of improved thermal conductivity.
Sainsbury et al., WO 2008/140583, discloses amine (NH2) modified BN nanotubes by exposure to NH3 plasma. Incorporation into a polymer is mentioned.
Ishida, U.S. Pat. No. 6,160,042, discloses boron nitride surface-treated with 1,4 phenylene diisocyanate incorporated into epoxy resins.
Mevellec et al., Chem. Mater. 2007, 19, 6323-6330, discloses that redox activation of aryl diazonium salts with iron powder in the presence of vinylic monomers in aqueous solution leads to very homogeneous thin polymer films strongly grafted on various surfaces such as (Au, Zn, Ti, stainless steel), glasses, carbon (nanotubes) or PTFE.
Epoxies and polyimides, are commonly used as components in printed circuit boards. As the density of elements in electronic circuits increases, heat management is an ever increasing problem. Incorporation into polymers of 50 volume % and more of hexagonal boron nitride (hBN) particles imparts enhanced thermal conductivity without compromising electrical insulation. In general, surface treatment of the BN particles is required in order to achieve adequate dispersion and moldability.
However, even with surface treatment, the high loading of hBN particles required for improved thermal conductivity in a given polymer causes a large increase in viscosity with concomitant degradation in processibility. This is especially a problem in producing substrate films for flexible printed circuit boards.